Ieat-insulating wall for refrigerators and cars



(No Model.)

O. B. HUTGHINS.

HEAT ANSULATING WALL POR REFRIGERATORS AND GARS. No. 339,188. Patented Apr. 6, 1886.l

Wlzef/mf.- I frz venianordinarily been obtained.

NTTED STATES PATENT OEEicE.

OARLETON B. HUTCHINS, OF DETROIT, MICHIGAN.

HEAT-INSULATING WALL FOR REFRIGERATORS AND CARS.

UIDECIFICATION forming part of Letters Patent No. 339,183, dated April 6, 1886.

(No model.)

To all whom it may concern.-

Beit known that I, CARLE'roN B. HUToH- INs, a citizen of the United States, residing in Detroit, in the county of rayne and State of Michigan, have invented a new and useful Improvement in Heat-Insulation Valls for Refrigerators and Gars, of which the following is a specification.

This invention relates to means for rendering the walls of refrigerator-chambers, and more especially refrigerator-cars,non-conducting to heat.

My purpose has been to produce a wall which shall be easily and cheaply constructed, not liable to be affected by changes in the atmospheric conditions of heat and moisture, which shall not be liable to become more pervious to heat by reason of the straining to which it may be subjected when used as the wall of a refrigerator-car, which is not liable to rapid decay or change of any kind, and which shall give a better1 insulation than has After considerable experiment, I find that these results can be best achieved by the following construction, which I will describe in connection with the accompanying drawing, showing a crosssection of my improved refrigerator-car, premising, however, that the present invention relates only to the means for producing heatinsulation,and not to the internal arrangement of the car.

In making a refrigerator car or chamber according to this invention, I construct the same of double wallsan outer wall, A, and an inner wall, B-leaving an open space between the two. In order that this open space may be left entirely clear and coextensive with the entire wall, I prefer to make the two Walls in some manner so that a frame-work may be dispensed with. This may be done in various ways; but the best method which I have thus far devised is the one indicated in the drawing, where the said walls are shown to be made of strips of wood nailed or secured latwise one upon another, as bricks are laid in a building. The object is to secure a strong self-supporting double-wall structure with a clear space, C, between the two walls, which may be readily filled. This clear space I fill with woolen rags cut into shreds, preferably of sulicient fmeness so that they will readily pack. Such rags may be obtained already shredded of the paper-makers, to whom they are of comparatively small value. Rags having some admixture of cotton may be employed, but not with the best results, because the cotton is more likely to absorb moisture, and thus to partially lose its insulating properties. I am aware that unmanu factured wool has been employed for this purpose; but my filling is better, cheaper, and more durable, packs better, and is less liable to change in bulk after packing.

I am' well aware that it has long been customary to construct the walls of refrigeratorchambers with a space to be filled with some packing material, such as sawdust, tan-bark, straw, dry leaves, and like vegetable substances; but these materials are exceedingly liable to absorb moisture readily, to engender fungoid and moldy growths, and to speedily decay, the result being that the chamber is liable to become tainted and to lose its insulation. I am also aware that asbestus has been used but, although less liable to change than the vegetable substances above named, it is almost equally subject to acquire dampness, and even when dry does not possess the desired non-conducting qualities. I am further fully aware of the fact that various coarser kinds of felt, made sometimes partly of hair and various sorts of paper, sometimes impregnated with antiseptic substances, have been used as a lining for refrigerating chambers. The objection to all such insulation is that the material is applied in the form of sheets secured to the surface of the wall by cement or nails or otherwise, and where employed in refrigerator-cars, even if a suiiicient thickness or number of layers to produce the requisite insulation be used, such structures, by reason of the racking of the ear, are liable to open at thejoints, iforiginally made tight, so that air-currents are engendered at some particular points and the insulation materially injured. nally produce a tight wall by means of insulating material applied in sheets. rThese difiiculties are entirely overcome by the use of the cut woolen rags lirmly packed in. Such a packing ol' woolen shreds is perrions to the air in every direction equally, and consequently it is exceedingly difiieult, if not im- Moreover, it is very difficult to origi- IOO possible, to engender any current in a particular direction.

I am informed that, theoretically, the best non conductor of heat known is 'a dead-air space, in which the air shall be perfectly motionless; but as any change in the temperature in the air at one point of such space is sure to cause a current and a consequent transmission of heat by convection, I have concluded that the airspace lled with the pervious unchanging material that I employ is the nearest approach to perfect heat-insula tion now known, as it is not liable to absorb moisture, not liable to decay and taints, may be equally and evenly packed, cannot sift out through small apertures, is exceedingly cheap CARLETON B. HUTCHINS.

In presence of- W. M. LILLIBRIDGE, E. R. HUTcHINs 

